# -*- coding: UTF-8 -*-
# filename: yangsy.py
# author by: Face
import random
def verif():
    num = int(input('请输入验证码长度：'))
    s = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    yzm = ''
    i = 0
    while i < num:
        yzm += str(random.choice(s))
        i += 1
    return yzm
c = verif()
print(c)